1 Watershed Management Plan Background The Ewa District AGENDA - - PDF document

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AGENDA

ʻEWA WATERSHED MANAGEMENT PLAN COMMUNITY MEETING #3 September 12, 2017 2

• Watershed Management Plan

Background

• The ʻEwa District
• ʻEwa Water Demand and Sources:

Existing (2010)

• ʻEwa Water Demand and Sources:

Future (2035)

• Watershed Management Projects

and Strategies

• WMP Approvals Process

WATERSHED MANAGEMENT PLAN BACKGROUND

ʻEWA WATERSHED MANAGEMENT PLAN COMMUNITY MEETING #3 September 12, 2017 3

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Planning Framework

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State Water Code State Water Code Oʻahu General Plan Oʻahu General Plan

Koʻolau Loa Koʻolau Loa Waiʻanae Waiʻanae Koʻolau Poko Koʻolau Poko North Shore North Shore ʻEwa ʻEwa Central Oʻahu Central Oʻahu PUC PUC East Honolulu East Honolulu

Oʻahu Water Management Plan

8 Watershed Management Plans By DP/SCP District

Oʻahu Water Management Plan

8 Watershed Management Plans By DP/SCP District

• Act 152: Watershed Protection
• Waiāhole Ditch Decision
• Ch 30, ROH Water Management
• BWS Sustainability Mission
• Act 152: Watershed Protection
• Waiāhole Ditch Decision
• Ch 30, ROH Water Management
• BWS Sustainability Mission

8 DP/SCP Land Use Plans 8 DP/SCP Land Use Plans

Hawaii Water Plan

• State Water Projects Plan
• Agricultural Water Use and Development Plan
• Water Quality Plan
• Water Resource Protection Plan
• County Water Use and Development Plans

Hawaii Water Plan

• State Water Projects Plan
• Agricultural Water Use and Development Plan
• Water Quality Plan
• Water Resource Protection Plan
• County Water Use and Development Plans
• County “Water Use and Development Plans” are required by the State Water Code
• “Oʻahu Water Management Plan” is required by Revised Ordinances of Honolulu

Chapter 30

• Honolulu Plans are district specific and called “Watershed Management Plans” (WMPs).

District‐level water and land use plans allow for community‐specific actions and strategies

• Guidance is provided by the Hawaiʻi Water Plan and the City’s ʻEwa Development Plan.
• WMPs require approval by BWS, DPP, City Council, and CWRM

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Watershed Management Plan Goal

To formulate an environmentally holistic, community based, and economically viable watershed management plan that will provide a balance between:

1. The protection, preservation, and management of Oʻahu’s watersheds 2. Sustainable ground and surface water use and development to serve present users and future generations.

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The WMP Goal applies to all of the Districts

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Watershed Management Plan Objectives

• 1. Promote sustainable watersheds;
• 2. Protect and enhance water quality and quantity;
• 3. Protect Native Hawaiian rights and traditional and customary

practices;

• 4. Facilitate public participation, education, and project

implementation; and

• 5. Meet future water demands at reasonable costs.

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The WMP Objectives apply to all of the Districts

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ʻEwa WMP Table of Contents

Chapters

Executive Summary 1. Oʻahu Water Management Plan Overview 2. ʻEwa Watershed Profile 3. Water Use and Projected Demand 4. Plan Objectives and Water Supply, and Watershed Management Projects and Strategies 5. Implementation

Appendices

• A. Oʻahu Watershed Management Plan Framework
• B. Plans, Policies, Guidelines, and Controls
• C. Oʻahu Water Use Permit Index
• D. Overview of Oʻahu Hydrogeology

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THE ʻEWA DISTRICT

ʻEWA WATERSHED MANAGEMENT PLAN COMMUNITY MEETING #3 September 12, 2017 8 (2009) (2016) (2009) (2012) (in progress) (in progress) (in progress) (FY ‘18)

Size: 33,677 acres (52.6 square miles) almost 1/10 of Oʻahu

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Hydrology and Water Sources

Northeast Trades Precipitation

Percolation

Evaporation

Transpiration Streams

Spring Spring Spring

Dike Confined Water Freshwater Aquifer

CAPROCK SEA LEVEL

Salt Water Salt Water

Perched Water

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Hydrology and Water Sources

• Impermeable caprock holds the fresh basal water

inland.

• Caprock also holds water from rainfall and leakage

from the basal aquifer in its limestone layers

Brackish Water Lens Salt Water Rainfall

Leakage from the basal aquifer to the caprock aquifer

Rainfall September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 10

In Ewa, there is a special geologic formation called “caprock.”

• The coastal plain is made up of sediments that form a relatively impermeable

sedimentary material, or “caprock.”

• The caprock restricts the seaward flow of fresh ground water.
• Caprock also holds water within its limestone layers. This water is fed by rainfall and

leakage from the basal aquifer.

• Irrigation from sugar plantations used to enhance the caprock aquifer, but since the

closing of Oahu Sugar Company (OSCo), the brackish caprock lens shrank.

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Climate

• Low rainfall
• Average annual rainfall in ʻEwa

= 20” - 40”

• Average annual rainfall on Oʻahu

= 20” – 300”

• Average annual rainfall for the State

= 10” – 440”

• Within the district, rainfall

decreases when going mauka to makai

• Average temperatures: 60˚ to 91˚

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Climate Change

Rainfall: Dry areas will get drier by 2100

Source: Figure developed by Abby Frazier, UH. Modified from data presented in Helweg et al. 2016 September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 12

Past

• Air temperature is increasing(0.3oF/decade over the past 30 years)1
• Rainfall has decreased by ‐15% over the past 20 years
• Rainstorm intensity has increased (+12%, 1958‐2007)1

Future

• There will be less rainfall by 2100 in leeward areas in both wet and dry seasons.
• Rainfall in the Koʻolau Mountains, especially in the Honolulu area, will increase in

the wet season.

• Implication: Leeward sources will deplete and more water will need to be

transported from the Pearl Harbor aquifer.

• ʻEwa will need to diversify it’s water sources, conservaon, recycled water and

limited desalination.

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ʻEwa’s Sugar History

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• 1897, Oahu Sugar Company established on the ʻEwa Plains
• 1925, 50,000 tons of sugar produced by ʻEwa Sugar Plantaon
• Sugar is a very thirsty crop, consuming 6,700 gpad (2004 WUDP) or 1,400‐5,000 gad

(IWREDSS duty), compared with 3,400 gpad for diversified ag in relatively dry areas

• By the 1930s, ʻEwa Plantaon, Oʻahu Sugar Company, Honolulu Plantaon = over 200

mgd from Pearl Harbor Aquifer to irrigate sugar on the ʻEwa Plains. (source: Sugar Water,

• p. 108)
• 1939‐1944, ~3,000 acres converted to military use
• 1970 Oahu Sugar Company acquired ʻEwa Plantaon
• 1988 OSCo Map of sugar lands; 13, 536 acres (out of 33,677 acres in ʻEwa)
• 1990, OSCo produced 76,925 tons of sugar on 11,526 culvated acres (ʻEwa and

Central), yielding 13.66 tons per acre.

• 1995, OSCo harvested last crop

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Full Buildout of Master Plans

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As sugar has declined, it has been replaced with many different land uses:

• Resort
• Industrial
• Residential
• Agriculture
• Military
• Kalaeloa

There are master plans for the development of most of ʻEwa

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ʻEwa Population: 1980-2010

20000 40000 60000 80000 100000 120000

1980 1990 2000 2010 1980 1990 2000 2010 Change (1980‐2010) Percent Change ʻEwa DP Area 35,709 42,983 68,696 101,397 65,688 184% Oʻahu Total 762,564 836,231 876,156 953,207 193,211 25% % of Oʻahu 5% 5% 8% 11% Resident Population

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• Over the past 30 years (1980 – 2010), ʻEwa populaon increased 184%
• It’s share of the total Oʻahu populaon increased from 5% to 11%

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ʻEwa Projected Population: 2010 - 2035

2010 2035 Change (2010‐2035) Percent Change ʻEwa DP Area 101,397 173,846 72,449 71% Oʻahu Total 953,207 1,071,225 118,017 12% % of Oʻahu 11% 16% 50,000 100,000 150,000 200,000 2010 2035

Resident Population

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• Over the next 25 years, the ʻEwa populaon is expected to grow by 71% and increase its

share of the total Oʻahu populaon from 11% to 16%

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Issues and Questions Raised

• Non-BWS water systems need to be accounted for
• What are the flooding issues?
• What is the state of the BWS water system in ʻEwa?
• Is our drinking water safe?
• Desalinated water: what will it be used for?
• Is there enough water for planned development?
• Protect traditional and customary practices
• Education and community engagement is important
• Land use and water planning needs to be integrated

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Issues raised in interviews and in previous community meetings

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ʻEWA WATER SOURCES

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• Ground Water
• Surface Water
• Storm Water
• Waiāhole Ditch
• Recycled Water
• Desalinated Water
• Salt Water

Ground Water

• Sustainable Yield (SY): the maximum rate at which water may

be withdrawn without impairing the utility or quality of the water source as determined by CWRM.

• Ground Water Management Area: special areas where

additional regulation is required

• The Pearl Harbor Aquifer Sector Area (ASA) is a Ground Water

Management Area.

• A CWRM water use permit is required for all ground water uses.

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SY basically sets the limits of what we can sustainably withdraw from that particular ground water aquifer

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Ground Water

ASYA = Aquifer System Area SY = Sustainable Yield September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 20

• The ‘Ewa Planning District overlays the Pearl Harbor Aquifer Sector Area.
• Aquifer Sector Areas are broken up into smaller units called Aquifer System Areas

(ASYA).

• ʻEwa overlays Makaīwa and a poron of the ʻEwa‐Kunia and Waipahu‐Waiawa ASYAs.
• Addionally, there is an ʻEwa Caprock Aquifer with three ASYAs: Kapolei, Malakole, and

Puʻuloa.

• SY for the Caprock aquifers is set by a chloride limit of 1,000 mg/l and is specific to

irrigation wells because it is the chloride level that is considered acceptable or irrigation.

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Basal Ground Water – PU and Pumpage (2010)

Aquifer System Area Sustainable Yield in MGD Permitted Use (PU) in MGD (% of SY) Pumpage in MGD (% of SY) Unallocated Sustainable Yield in MGD (% of SY) SY Minus Pumpage in MGD (% of SY) ʻEwa‐Kunia 16 14.3 (89% of SY) 12.3 (77% of SY) 1.7 (11% of SY) 3.7 (23% of SY) Waipahu‐ Waiawa (ʻEwa only) 104 15.8 (15% of SY) 3.2 (3% of SY) 19.1 (18% of SY) 74.9 (72% of SY) Waipahu‐ Waiawa (Entire ASYA) 84.9 (82% of SY) 29.1 (28% of SY) TOTAL (ʻEwa only) 120 30.1 (25% of SY) 15.5 (13% of SY) 20.8 (17% of SY) 78.6 (65% of SY) TOTAL (Entire ASYA) 99.2 (83% of SY) 41.4 (35% of SY)

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• Permitted Use is the amount of water that CWRM has allocated to water users in the

form of permits

• Pumpage is what CWRM has on record from self‐reporting
• Unallocated SY = SY – PU
• Pumpage is generally less that the permitted amount
• We are currently permitting and pumping less than the SY for both aquifers

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Caprock Ground Water – PU and Pumpage (2010)

Aquifer System Area Permitted Use (MGD) Pumpage (MGD)

Makaīwa 0.072 0.00 Malakole 7.011 2.76 Kapolei 2.333 0.75 Puʻuloa 11.924 3.18 TOTAL 58.865 6.69

Sustainable Yields for these caprock aquifers are set by a chloride limit of 1,000 mg/L.

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Ground Water – Import from Central Oʻahu (2010)

Water System Import (MGD) ASYA

BWS 7.2 Waipahu‐Waiawa JBPHH 0.6 Waipahu‐Waiawa TOTAL 7.8

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Surface Water

• One (1) perennial

Stream

• 16 dry streams or

gulches

• Wetlands in the

Honouliuli and Kalaeloa units of the Pearl Harbor National Wildlife Refuge

• No current offstream

use

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Storm Water

• Currently limited use of storm water for golf course irrigation
• Challenges: low average rainfall
• Opportunities:
• Deep infiltration trench to capture storm water for recharging the

shallow brackish aquifer

• Storm water from Wheeler Army Air Force Base could be made

available for use in Kunia and ʻEwa

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Waiāhole Ditch: SY = 15 MGD

USE CENTRAL OʻAHU (2010, MGD) ʻEWA (2010, MGD) TOTAL Sustainable Yield 15.0 Permitted Offstream Uses 8.731 4.260 12.991 Unallocated Water 2.009 Reported Use 3.093 3.644 6.737

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Recycled Water – Honouliuli Water Recycling Facility

RECYCLED WATER CLASSIFICATION CAPACITY IN 2010 (MGD) DEMAND IN 2010 (MGD) END USE R‐1 10 7.012 dust control, industrial, golf course and landscape irrigation R‐O 2 1.385 industrial TOTAL 12 8.397

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Desalinated Water

• BWS Recycled Water Facility
• Desalinates R-O water for industrial uses
• Private Desalination Facilities
• Small, demineralizing facilities for industrial uses
• Proposed Desalination Plants (BWS)
• Kalaeloa Seawater Desalination Plant
• Kapolei Brackish Water Desalination Plant

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Salt Water

• 37.5 MGD of salt water permitted for industrial cooling in 2010
• 12.2 MGD reported salt water pumpage in 2010
• Salt water is not counted against aquifer sustainable yield

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ʻEWA WATER SYSTEMS

ʻEWA WATERSHED MANAGEMENT PLAN COMMUNITY MEETING #3 September 12, 2017 30

• Honolulu Board of Water Supply
• City and County of Honolulu
• State of Hawaiʻi
• Federal
• Private

Honolulu BWS: Potable Water System

• Sources: basal

ground water

• Within the ʻEwa

District

• Imported from

Central Oʻahu

• Quality: potable
• Use:

domestic residential and non-residential

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This map generally shows where BWS services, although it does not service quite as far mauka along Kunia Road.

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Honolulu BWS: Non-Potable Water System

• Sources:
• Basal ground water

(ʻEwa-Kunia ASYA)

• Caprock aquifer

(Kapolei ASYA)

• Use:

landscape irrigation

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Honolulu BWS: Recycled Water System

• Source:

Honouliuli Water Recycling Facility

• Quality:

R-1, R-O

• Uses:

irrigation, industrial

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R‐1 Quality Recycled Water (10 mgd capacity)

• Dust control, industrial, golf course irrigation, landscape irrigation

R‐O Quality Recycled Water (2 mgd capacity)

• Refineries, Power Plants

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City and County of Honolulu Water Systems

• Department of

Environmental Services

• Source: caprock aquifer

(Puʻuloa ASYA)

• Quality: non-potable
• Use: industrial
• Department of Parks and

Recreation

• Source: caprock aquifer

(Puʻuloa ASYA)

• Quality: non-potable
• Use:

landscape irrigation

ENV/ DPR September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 34

State of Hawaiʻi Water Systems

• Waiāhole Ditch

(Agribusiness Development Corporation)

• Source: ground water

imported from Windward Oʻahu

• Quality: non-potable
• Use: agriculture
• Hawaiʻi Housing Finance

and Development Corporation

• Source: caprock aquifer

(Kapolei ASYA)

• Quality: non-potable
• Use:

landscape irrigation

HHFDC WAIĀHOLE DITCH September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 35

Federal Water Systems

• Kalaeloa Water System
• Source:

basal aquifer

• Quality:

potable

• Use:

residential, non-residential, irrigation

• Joint Base Pearl Harbor-Hickam
• Source:

basal aquifer (imported from Central Oʻahu)

• Quality:

potable

• Use:

residential

• U.S. Navy
• Source:

caprock aquifer (Puʻuloa ASYA)

• Quality:

non-potable

• Use:

agriculture

• USFWS
• Source:

caprock aquifer (Puʻuloa ASYA)

• Quality:

non-potable

• Use:

irrigation Kalaeloa Water System JBPHH

U.S. Navy US FWS

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Private Water Systems

• Source:

basal aquifers

• Quality:

non-potable

• Uses:

agriculture, industrial, golf course, landscape irrigation

• Source:

caprock aquifers

• Quality:

non-potable

• Uses:

industrial, golf course, landscape irrigation

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ʻEWA WATER DEMAND AND SOURCES: EXISTING (2010)

ʻEWA WATERSHED MANAGEMENT PLAN COMMUNITY MEETING #3 September 12, 2017 38

Agriculture 7.0 MGD

Existing Water Demand in ʻEwa (2010)

Desalted Water Recycled Water Conser‐ vation Surface Water Ground Water Salt Water Domestic

(Residential, Commercial, etc.)

19.0 MGD Industrial 7.2 MGD Landscape Irrigation 8.7 MGD Natural Resource Protection Storm Water

In‐district Waipahu‐ Waiawa & ʻEwa‐ Kunia ASYA R‐0 In‐district Non‐ Potable Imported Waipahu‐ Waiawa ASYA Imported (WDIS)

Traditional & Customary Practices

R‐1

In situ uses

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Existing (2010) ʻEwa Water Demand: Use Categories

Water Use Category ( MGD) ( %) Domestic Residential 12.5 30% Domestic Non‐Residential 6.5 15% Industrial1, 2 7.2 17% Agriculture 7.0 17% Golf Course Irrigation2 7.5 18% Landscape Irrigation2 1.2 3% TOTAL 41.9 100%

1 Industrial water demands do not include demands for salt water. 2 Industrial and irrigation demands include demands for recycled water.

2010 Water Demand

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Existing (2010) ʻEwa Water Supply

Ground Water (Fresh Water Aquifer) 16.2 MGD, 38% Ground Water (Bracksh Caprock Aquifer) 6.7 MGD, 16% Waiāhole Ditch Irrigation System 3.6 MGD, 9% Import from Central Oʻahu 7.8, MGD 18% Recycled Water (R‐1) 7.0 MGD, 16% Recycled Water (R‐O) 1.4 MGD, 3%

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Existing (2010) ʻEwa Water Demand: BWS Potable System

Residential 10.59 MGD (62%) Hotel/Report 0.12 MGD (1%) Industrial 1.71 MGD (10%) Golf Course & Landscape Irrigation 0.60 MGD (4%) Religious 0.02 MGD (0%) City Government 0.09 MGD (0%) Commercial 3.35 MGD (20%) Agriculture 0.19 MGD (1%) Other 0.0 MGD (0%) U.S. Government 0.03 MGD (0%) State Government 0.37 MGD (2%)

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BWS Existing (2010) water demand = 19 MGD

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ʻEWA WATER DEMAND AND SOURCES: FUTURE (2035)

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• Water Demand Projections
• Water Demand Scenarios
• Base Case (Mid-Growth) Scenario
• Ultimate-Growth Scenario

Future ʻEwa Water Demand: Projections

• The Statewide Framework for Updating

the Hawaiʻi Water Plan (Statewide Framework)

• All water producers: BWS, Federal, State,

and Private

• Develop “a range of forecasts”

(1) Low-growth (2) Mid-growth (City projections based on land use policies) (3) High-growth

• ʻEwa WMP also developed an “Ultimate-

growth” scenario

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Ultimate growth scenario is in addition to the recommended “range of forecasts” prescribed by the Framework

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Future ʻEwa Water Demand: Scenarios

Scenario Description Population Increase 2010 ‐ 2035 Low‐Growth ʻEwa does not develop into the Secondary Urban Center and Oʻahu residents connue to work and reside in the Primary Urban Center. + 37,540 people Mid‐Growth City population projections based on the General Plan and ʻEwa Development Plan recognize that Kapolei becomes the Secondary Urban Center of Oʻahu. + 62,567 people High‐Growth The Second City of Kapolei has come into its own. ʻEwa is a successful job center and Kalaeloa is being developed. + 104,278 people Ultimate‐ Growth Kapolei and Kalaeloa rival Downtown Honolulu as job centers and all planned residential units have been developed. + 243,341 people (2010 ‐ ~2080)

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Future ʻEwa Water Demand in MGD

SCENARIO DOMESTIC AGRICULTURE INDUSTRIAL GOLF COURSE LANDSCAPE IRRIGATION TOTAL (% increase) Existing (2010) 19.0 7.0 7.2 7.5 1.2 41.9 Low‐ Growth (2035) 21.7 5.1 8.2 7.5 1.7 44.2 (5%) Mid‐ Growth (2035) 26.9 4.0 8.5 7.5 3.4 50.2 (20%) High‐ Growth (2035) 34.3 6.1 11.4 8.3 3.8 63.9 (53%) Ultimate‐ Growth 42.7 7.6 11.9 9.5 5.9 77.6 (85%)

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Mid‐growth = base case (“most likely”) scenario

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Future ʻEwa Water Demand: Mid-Growth Scenario

Growth Scenario Water Demand (MGD)

41.9 44.2 50.2 63.9 77.6

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 Baseline (2010) Low‐Growth (2035) Mid‐Growth (2035) High‐Growth (2035) Ultimate‐Growth September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 47

ʻEwa Development Plan Policies

ʻEwa’s Role in Oʻahu’s Development Pattern

• Second urban center for Oʻahu;
• Wide range of master planned residential;
• Diversified agriculture on prime agricultural lands along Kunia Road and in the

Explosive Safety Quantity Distance arc; and

• Resort areas at KoʻOlina and at Ocean Pointe.

Water Use Efficiency and Conservation

• Implement water conservation measures and reduce water loss;
• Prioritize recycled water and brackish ground water as non-potable irrigation

sources;

• Meet agricultural water needs with such potential sources as caprock, surface

water, spring waters, Waiāhole Ditch Water, and recycled water.

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The ʻEwa Development Plan helped to shape the Watershed Management Plan policies regarding water supply.

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ʻEwa Development Plan Policies

• Develop alternative water

supplies using new technologies

• water reclamation
• desalination
• deep ocean water applications
• Encourage use of technologies

conserving water and using renewable energy that could support alternative water supplies

• seawater air conditioning
• photovoltaics
• efficient plumbing and lighting

fixtures

• wave energy
• bio-fuels.

Alternative Water Supplies

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ʻEwa WMP Water Policies

1. Continue to reduce ʻEwa’s per capita water demand, to the amount feasible, by implementing water conservation programs at all levels of use: domestic, industrial, agricultural, and irrigation. 2. Reserve potable water sources for potable needs. 3. Incrementally convert non-potable uses that are currently using potable water to non-potable sources. 4. Maximize the use of recycled water. 5. Minimize the need for increased import of potable water from Central Oʻahu ground water aquifers. 6. Replenish the ʻEwa caprock aquifer and use this source for non-potable uses. 7. Continue efforts to provide economically-competitive desalinated water that allows us to adapt to climate change.

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Agriculture

Future ʻEwa Water Supply: Mid-Growth Scenario

Desalted Water Recycled Water Conser‐ vation Surface Water Ground Water Salt Water Domestic

(Residential, Commercial, etc.)

Industrial Landscape Irrigation Natural Resource Protection Storm Water

In‐district Waipahu‐ Waiawa & ʻEwa‐ Kunia ASYA R‐0 In‐district Non‐ Potable Imported Waipahu‐ Waiawa ASYA Imported (WDIS)

Traditional & Customary Practices

R‐1

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ʻEwa Water Supply: Mid-Growth Scenario

WATER SOURCE DOMESTIC AGRI‐ CULTURE INDUSTRIAL GOLF COURSE LANDSCAPE IRRIGATION TOTAL BASAL GROUND WATER 21.8 3.2 0.2 ‐‐‐ 1.0 26.2 CAPROCK GROUND WATER ‐‐‐ 0.5 3.0 2.7 3.5 9.7 IMPORT: PEARL HARBOR AQUIFER 4.1 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ 4.1 WAIĀHOLE DITCH ‐‐‐ 4.1 ‐‐‐ ‐‐‐ ‐‐‐ 4.1 RECYCLED WATER (R‐1, R‐O) ‐‐‐ ‐‐‐ 6.0 5.0 3.5 14.5 DESALINATED WATER 1.7 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ 1.7 STORM WATER ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ TOTAL SUPPLY 27.6 7.8 9.2 7.8 8.0 60.3 TOTAL DEMAND 26.9 4.0 8.5 7.5 3.4 50.2

NOTE: Total supply figures are rounded

• No basal ground water for golf course irrigation
• Use caprock for all non‐potable demands
• Import only for domestic use (Pearl Harbor aquifer) or agriculture (Waiāhole Ditch)
• Increase use of recycled water
• Diversify domestic source with desalinated water
• No use of storm water due to the unreliable nature of rainfall in ʻEwa

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ʻEwa Water Supply: Mid-Growth Scenario

41.9 43.5 43.9 45.1 47.1 50.2

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 2010 2015 2020 2025 2030 2035

MGD Year

Desalination Facilities Honouliuli WRF (R‐1) Honouliuli WRF (R‐O) Waiāhole Ditch ASYA Puʻuloa ASYA Kapolei ASYA Malakole ASYA Makaīwa ASYA Waipahu‐Waiawa ASYA (import) Waipahu‐Waiawa ASYA (in‐district) ʻEwa‐Kunia ASYA TOTAL WATER DEMAND

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• Increase in‐district ground water use allows decrease in import
• No change in Waiāhole Ditch water
• Increase in recycled water use and desalinated water

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ʻEwa Water Supply: Two Ultimate-Growth Scenarios

Moderate Application of Water Policies

• BWS per capita water demand of 160 gallon per capita day (GPCD) – same as in

Mid-Growth Scenario

• Irrigation per acre water demand same as in Mid-Growth Scenario

Aggressive Application of Water Policies

• Aggressive application of conservation efforts decrease domestic water demand
• Decrease BWS per capita water demand from 160 GPCD to 150 GPCD
• Decrease Kalaeloa and JBPHH demand by 10% from “Moderate Ultimate” Scenario
• Climate change causes a 15% increase in agriculture and landscape irrigation

water demand from “Moderate Ultimate” Scenario due to less rainfall and higher temperatures

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The Ultimate‐Growth Scenario was developed to stress the limits of water resources to see what we could and should do. The first pass at an Ultimate‐Growth Scenario assumed full buildout of all of the known land use master plans, but no other changes in calculating water demand. We found that these water demands could be met with a moderate application of the water policies. A second Ultimate‐Growth Scenario was developed to see what it would look like if we were aggressive in our application of the water policies. BWS per capita demand

• 185 GPCD (2010)
• 160 GPCD (2035, all scenarios, incl. moderate Ultimate)
• 150 GPCD (aggressive Ultimate)

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ʻEwa Water Supply: Ultimate-Growth Scenario (Moderate)

WATER SOURCE DOMESTIC AGRI‐ CULTURE INDUSTRIAL GOLF COURSE LANDSCAPE IRRIGATION TOTAL BASAL GROUND WATER 26.8 +2 (unknown source) 4.2 0.2 ‐‐‐ 1.0 34.2 CAPROCK GROUND WATER ‐‐‐ 1.5 3.5 6.6 7.6 19.2 IMPORT: PEARL HARBOR AQUIFER 10.1 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ 10.1 WAIĀHOLE DITCH ‐‐‐ 4.1 ‐‐‐ ‐‐‐ ‐‐‐ 4.1 RECYCLED WATER (R‐1, R‐O) ‐‐‐ 1.5 8.5 6.5 5.0 21.5 DESALINATED WATER 5.0 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ 5.0 STORM WATER ‐‐‐ 1.0 ‐‐‐ ‐‐‐ ‐‐‐ 1.0 TOTAL SUPPLY 43.9 12.3 12.2 13.1 13.6 95.1 TOTAL DEMAND 42.7 7.6 11.9 9.5 5.9 77.6

NOTE: Total supply figures are rounded

• Note that Kalaeloa may exceed its ground water permit and will need to find additional

source

• Still no basal ground water used for golf course irrigation
• Use caprock for all non‐potable demands
• Import only for domestic use (Pearl Harbor aquifer) or agriculture (Waiāhole Ditch).

Import from Pearl Harbor increases.

• Increase use of recycled water. Begin to use recycled water for agriculture.
• Diversify domestic source with desalinated water.
• Begin to use storm water for agriculture.

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ʻEwa Water Supply: Ultimate-Growth Scenario (Moderate)

41.9 77.6

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

2010 Ultimate

Storm Water Waiāhole Ditch Recycled (R‐0) Recycled (R‐1) Puʻuloa AYSA Kapolei AYSA Malakole ASYA Makaīwa ASYA Desalination Waipahu‐Waiawa ASYA (import) Waipahu‐Waiawa ASYA (in‐district) ʻEwa‐Kunia ASYA TOTAL WATER DEMAND

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• Increased in‐district ground water use allows a decrease in imported water
• Increase use of caprock water
• Increase in recycled water use and desalinated water
• Add storm water

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ʻEwa Water Supply: Ultimate-Growth Scenario (Aggressive)

WATER SOURCE DOMESTIC AGRI‐ CULTURE INDUSTRIAL GOLF COURSE LANDSCAPE IRRIGATION TOTAL BASAL GROUND WATER 27.8

+1.5 (unknown source)

‐‐‐ ‐‐‐ ‐‐‐ 1.0 30.3 CAPROCK GROUND WATER ‐‐‐ ‐‐‐ 0.5 ‐‐‐ 1.6 2.1 IMPORT: PEARL HARBOR AQUIFER 6.6 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ 6.6 WAIĀHOLE DITCH ‐‐‐ 4.1 ‐‐‐ ‐‐‐ ‐‐‐ 4.1 RECYCLED WATER (R‐1, R‐O) ‐‐‐ 4.2 11.5 10 4.7 30.4 DESALINATED WATER 5.0 ‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ 5.0 STORM WATER ‐‐‐ 1.0 ‐‐‐ ‐‐‐ ‐‐‐ 1.0 TOTAL SUPPLY 40.9 9.4 12.0 10.0 7.3 79.6 TOTAL DEMAND 39.8 7.8 11.9 9.5 6.4 75.5

The previous supply scenario was able to meet the Ultimate demand by moderately applying the water policies. This supply scenario looked at what supply would look like if we were to be more aggressive in applying the water policies. NOTE: Total supply figures are rounded Supply

• With additional conservation, Kalaeloa may still exceed its ground water permit and will

need to find additional source

• No basal ground water for golf course, agriculture, and industrial uses
• Less import needed from Pearl Harbor
• Import only for domestic use (Pearl Harbor aquifer) or agriculture (Waiāhole Ditch).

Import from Pearl Harbor decreases from moderate application of water policies.

• Recycled water helps supply all non‐potable demand categories, replacing basal and

caprock ground water for ag and golf course and lessening landscape irrigation and industrial demands for caprock water.

• Diversify domestic source with desalinated water.
• Use storm water for agriculture.

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ʻEwa Water Supply: Ultimate-Growth Scenario (Aggressive)

41.9 75.5

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0

2010 Ultimate

Storm Water Waiāhole Ditch Recycled (R‐0) Recycled (R‐1) Puʻuloa AYSA Kapolei AYSA Malakole ASYA Makaīwa ASYA Desalination Waipahu‐Waiawa ASYA (import) Waipahu‐Waiawa ASYA (in‐district) ʻEwa‐Kunia ASYA TOTAL WATER DEMAND

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Maximizing use of recycled water allows for :

• Decreased import from Pearl Harbor
• Replacement of in‐district basal ground water for agriculture, industrial uses, and golf

course irrigation, and a decrease in its use for landscape irrigation

• Replacement of in‐district caprock water for agriculture and golf course irrigation, and a

decrease in its use for industrial and landscape irrigation

58

ʻEwa Water Demand and Supply

41.9 50.2 77.6 75.5

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 2010 2035 ULTIMATE ULTIMATE

Storm Water Waiāhole Ditch Recycled (R‐0) Recycled (R‐1) Puʻuloa AYSA Kapolei AYSA Malakole ASYA Makaīwa ASYA Desalination Waipahu‐Waiawa ASYA (import) Waipahu‐Waiawa ASYA (in‐district) ʻEwa‐Kunia ASYA TOTAL WATER DEMAND

MID‐ GROWTH SCENARIO MODERATE WATER POLICIES AGGRESSIVE WATER POLICIES

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WATERSHED MANAGEMENT PROJECTS AND STRATEGIES

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Projects with Champions Specific projects that are being planned and/or that are being implemented by a particular agency or agencies or by a particular group or non-profit entity. Strategies Potential actions that would serve to implement the overall goal, objectives, and sub-objectives of the WMP, but that do not currently have a project champion.

Projects with Champions

5 4 3 3 1 6 7 8 9 10 11 12 13 14 15

BWS System‐wide Projects

2

Water Supply Projects 1. Honouliuli Water Recycling Facility 2. Caprock Aquifer Storage and Recovery (ASR) 3. Brackish and Seawater Desalination 4. Waiāhole Ditch Water Loss Minimization 5. Water Infrastructure for Agricultural Expansion Mauka of H‐1 Freeway 6. Water Infrastructure for Navy ESQD Zone 7. Kalaeloa Water System Improvements Watershed Management Projects 8. Kalaeloa Heritage Park 9. Hoakalei Coastal Village Restoration 10. Mālama Learning Center 11. Anchialine Pool Restoration 12. Waiʻanae Mountains Watershed Partnership BWS “System‐Wide” Projects 13. Potable Source Water Protection 14. Assess Resiliency of Critical Water Infrastructure 15. BWS Infrastructure Renewal and Replacement Program

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Watershed Management Strategies

A C E H J D B F I G K

Broad Geographic Distribution

L

A. Waiāhole Ditch Augmentation B. Brackish Well Development C. Industrial Cooling Using Seawater D. Grey Water Reuse E. Kaloʻi Gulch Regional Drainage Plan Evaluation F. Stormwater Retention/Detention – including golf course detention G. Renewable Energy Opportunities H. ʻEwa Caprock District Cooling I. Convert Cesspools to Municipal Sewer System J. Integrate Planning for Land Use and Water Resources Management K. ʻEwa Sustainability Dialogues L. Potable Source Water Protection

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WATERSHED MANAGEMENT PLAN APPROVALS PROCESS

ʻEWA WATERSHED MANAGEMENT PLAN COMMUNITY MEETING #3 September 12, 2017 63

ʻEwa WMP Approvals Process

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

2017

CITY COUNCIL Adoption by Ordinance

• 3 Council Readings
• Public Hearing
• Committee Meetings

ʻEWA PRE‐FINAL DRAFT

2018

NEIGHBORHOOD BOARD ENDORSEMENTS CWRM 90 Day Notice Public Hearing CWRM Meeting & Approval DRAFT ʻEWA WMP COMMENT PERIOD September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 64

DRAFT ʻEWA WATERSHED MANAGEMENT PLAN

HARD COPIES

ʻEwa Beach Public and School Library 91-950 North Road ʻEwa Beach, HI 96706 Kapolei Public Library 1020 Manawai Street Kapolei, HI 96707 Hawaiʻi State Library 478 S. King Street Honolulu, HI 96813

PDF COPY

http://www.boardofwatersupply.com/water- resources/watershed-management-plan/ewa- plan

Please submit comments by October 31, 2017 to:

Email: sherri@townscapeinc.com Townscape, Inc. Attn: Sherri Hiraoka 900 Fort Street Mall, Suite 1160 Honolulu, HI 96813

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Contact Information

BOARD OF WATER SUPPLY

Barry Usagawa Honolulu Board of Water Supply busagawa@hbws.org (808 748-5900

TOWNSCAPE, INC.

Sherri Hiraoka Townscape, Inc. sherri@townscapeinc.com (808) 536-6999, ext. 6

DRAFT ʻEWA WATERSHED MANAGEMENT PLAN AND PREVIOUS COMMUNITY MEETING PRESENTATIONS AND NOTES MAY BE FOUND ON-LINE AT: http://www.boardofwatersupply.com/water-resources/watershed-management-plan/ewa-plan

September 12, 2017 ʻEWA WATERSHED MANAGEMENT PLAN – COMMUNITY MEETING #3 66